Google Duo allows you to call people who don't have the app

Google has quietly made its Duo video messaging app far more useful, enabling audio and video calls even if the person you're contacting hasn't installed the app. People who don't have Duo installed on their Android smartphone experience calls just like Duo users: All the features of a normal video call and audio call such as Knock Knock, mic muting, and camera switching are present on and accounted for on the App Preview version of Duo.

The new addition works exactly like a usual Duo call which includes the Knock-Knock feature through which you can see the preview of the caller before you pick it up. There is also a notification icon that is persistent and it can bring the call into view even on navigating away from the call.

At the end of the call, these users will be prompted to install the Duo app; that will remain a choice. The user also noted that he was able to make a Duo call to this Nexus 6P.

To make this happen, the search giant's using a Google Play Services feature called App Preview Messaging, which launched alongside Allo, Google's text messaging platform, in 2016. If you want to turn off receiving messages and calls from not-yet-installed apps altogether, meanwhile, you can do that in the Android settings. However, it does not let you do activities like sending attachments or images and changing the text size by dragging the send button up or down. With the update, Google Duo users can now call people that haven't ever installed or registered with Duo in the past. However, this isn't going to work with everybody on your contact list - iPhones and other non-Android devices are obviously off limits. Phone contacts that can receive Duo calls will now appear in your Duo contacts list without an invite symbol next to them.